Field of the invention
The field of the invention relates to cutting tools for performing a number of different cutting functions without necessitating retooling or the use of different cutting tool apparatuses.
Heretofore, boring and horizontal cutting operations required the use of at least two separate and distinct types of cutting tools. Boring operations, i.e. direct and vertical penetration into a substrate were typically performed by a twist drill bit powered by a conventional drill or drill press. Because of the configuration and placement of their cutting edges and flutes, twist drills are generally ineffective for cutting in directions anything other than vertically. Examples of conventional twist drills are described, for example, in U.S. Pat. Nos. 2,936,658 which issued to O. L. Riley on May 17, 1960; 2,778,252 which issued to C. J. Oxford, Jr. on Jan. 22, 1957; 2,966,081 which issued to W. J. Kallio on Dec. 27, 1960; and 4,116,580 which issued to R. F. Hall et al. on Sept. 26, 1978.
Horizontal cutting operations such as, for example, traverse cutting or slotting were typically performed by an end mill powered by the conventional milling machine. Generally, end mills include their cutting surfaces on the side surfaces of the tool in order to effect such operations. Typically, as exemplified by the milling tool described in U.S. Pat. No. 2,360,425 which issued to F. Kinzbach on Oct. 11, 1941, end mills will generally have square or ball noses which are inefficient for boring operations. Because of this inefficiency to bore or penetrate vertically, when a slot is to be cut in a substrate, a twist drill has been used to bore the initial hole and then an end mill is used to horizontally cut or groove.
A third type of cutting operation oftentimes required is a chamfering operation wherein the edges of a substrate are routed or angled or where a "V" shaped groove is to be cut in the substrate. Historically, this chamfering or grooving operation has been performed by tilting or angling conventional flat or square nose end mills to the desired angle to angularly cut. Such a technique, however, requires a milling machine with a rotatable head capable of cutting at an angle.
As can be readily appreciated, the fact that all three of these cutting operations either require different cutting tools or a special milling machine with a rotatable head, conventional cutting tools presently available are somewhat inefficient. A substantial amount of worker's time is required to change cutting tools and cutting tool apparatuses when different cuts are to be made and further necessitates the stocking of a number of different twist drills and end mills and apparatuses to power both. Further, with the advent and extensive use of numerically controlled (N.C.) milling and drilling operations, the manual changing of cutting tools and even the automatic indexing of machine turrets to effect these different operations reduces the benefits otherwise obtainable from such computerized automatic equipment. It is readily apparent that a single tool which can perform a number or all of these cutting functions and which is adaptable to N.C. milling and drilling operations offers numerous commercial advantages.
Attempts at combining a number of these cutting operations have been tried in the past. For example, U.S. Pat. No. 3,058,199 which issued to R. S. Cave et al. on Oct. 16, 1962 describes a cutting tool which combined the features of routing and milling cutters, both being essentially horizontal cutting operations. See also U.S. Pat. No. 3,667,857 which issued to M. W. Shaner et al. on June 6, 1972 for a combined twist drill and reamer cutting tool, both functions of which are boring operations. Applicant is, however, unaware of any commercially available cutting tool which is capable of effectively performing both vertical and horizontal cutting operations and which will further accomplish a chamfering operation.
Against the foregoing background, it is a primary objective of the present invention to provide a combination cutting tool which is capable of effectively performing horizontal and vertical cutting operations.
It is another objective of the present invention to provide a combination cutting tool capable of effectively performing boring, slotting and chamfering operations.
It is still another objective of the present invention to provide a combination cutting tool capable of performing horizontal and vertical cutting operations and which is compatible with numerically controlled milling and drilling equipment.